02272naa a2200217 a 450000100080000000500110000800800410001910000200006024501600008026000090024052015670024965300080181670000250182470000250184970000170187470000190189170000250191070000170193570000200195277300820197219221382015-07-20       2012    bl uuuu     u00u1 u    #d1 aOLIVEIRA, A. C.  aErythroxylum pungens elicits vasorelaxation by reducing intracellular calcium concentration in vascular smooth muscle cells of rats.h[electronic resource]  c2012  aThe cardiovascular effects elicited by the ethanolic extract obtained from the roots of Erythroxylum pungens O.E. Schulz, Erythroxylaceae (EEEP) and the vasorelaxant effect induced by its main tropane alkaloid (pungencine) were investigated. In normotensive rats, administration of EEEP (1, 10, 30 and 60 mg/kg i.v., randomly) produced dose-dependent hypotension (-2±1, -7±0.5 -17.6±1, -24±1 ? mmHg, n=5) followed by tachycardia (3±0.5, 7±2, 7.1±1, 10±5 ? bpm, n=5). In intact phenylephrine (Phe, 10 ?M)-pre-contracted rings, EEEP (0.01-500 ?g/mL) induced concentrationdependent vasorelaxation (EC50 13.7±5.5 ?g/mL, Maximal Response= 92±2.6%), and this effect was unchanged after the removal of the vascular endothelium (EC50 27.2±4.7 ?g/ml, Maximal Response= 88.3±3.3 %). In KCl (80 mM)-pre-contracted-endotheliumdenuded rings, EEEP elicited concentration-dependent relaxation (EC50= 128.2±11.2 ?g/mL, Maximal Response 76.8±3.4%). Vasorelaxation has also been achieved with tonic contractions evoked by the L-type Ca2+ channel agonist Bay K 8644 (EC50 80.2±9.1 ?g/mL, Maximal Response 86.3±8.3%). In addition, in a depolarizing medium, EEEP inhibited CaCl2 (30-500 ?g/mL) induced contractions and caused a concentrationdependent rightward shift of the relaxation curves. Lastly, the tropane alkaloid pungencine caused vasorelaxation in mesenteric arteries resembling to the EEEP responses. These results suggests that EEEP induces hypotension and vasorelaxation, at least in part, due to the reduction in [Ca2+]i in vascular smooth muscle cells.  aRat1 aSENA FILHO, J. G. de1 aMENDES JUNIRO, L. G.1 aANJOS, R. M.1 aRIBEIRO, T. P.1 aBARBOSA FILHO, J. M.1 aBRAGA, V. A.1 aMEDEIROS, I. A.  tRevista Brasileira de Farmacognosiagv. 22, n. 2, p. 436-442, mar./apr. 2012.